1. Field of the Invention
In one aspect this invention relates to the protective grills used in armored vehicles. In a further aspect this invention relates to a unique structure for protecting armored vehicles from ballistic particles while allowing airflow through the grill.
2. Prior Art
In general ballistic grilles have traditionally been made with a plurality of shaped, chevron or s-curve shaped slats arranged in an overlapping pattern. The slats are arranged so there is no direct straight-line path by which a projectile can pass from the outside through the grill. Various different arrangements are used and the slats have been formed with different materials so as the fragment or projectile hits the grill the particle is slowed and the force is then absorbed with the ballistic fragment or projectile being trapped in the grill.
Such designs have been used for decades with little or no basic change in design other than an occasional change in material or spacing to increase shock absorption or reduce particle ricochet.
Briefly, the present invention is a foraminated, laminated ballistic grill for armored vehicles. The grill is attached to a vehicle so as to protect vital vehicle components while still allowing cooling air to enter one or mote interior chambers of the vehicle. The grill has a hard outer ballistic layer of a ballistic material designed to stop deflect and/or fragment projectiles and other ballistic particles. The outer surface of the ballistic layer is formed with a textured surface having a plurality of projections. One example is to form the projections with a plurality of facets or other faces, these surfaces being disposed at an angle to the body of the ballistic layer. Forming the outermost surface with a texture presents a target surface that will interact with the incident projectiles and particles at an angle thereby minimizing the normal force the particle exerts on the ballistic layer and consequently reducing the particle""s penetrating power.
The grill""s ductile inner layer will be formed from a softer material adapted to trap and contain ballistic fragments and projectile pieces which have entered the apertures or penetrated the outer ballistic surface of the grill structure.
The grill has a multiplicity of shaped formanina passing through the inner and outer layers to provide a path for cooling air from the ambient atmosphere into the interior of the vehicle. Each of the foramina has a relatively small first opening on the outer surface of the ballistic panel in fluid contact with the ambient atmosphere to allow air flow into the grill and a second opening on the inner surface of the panel to allow air flow into a compartment within the vehicle. The first and second openings are offset from each other and connected by a curved channel. The channel provides the means of airflow between the first and second openings and is shaped so that at least a portion of the channel is offset from the longitudinal axis of the first opening. Thus, a particle that enters the first opening is forced to travel a curved tortuous path within the channel and will tend to burrow into the inner layer for entrapment.